Rats are the optimal model for many research studies aimed at gaining a better understanding of human health and developing more effective cures and therapies for human diseases. The Rat Resource and Research Center (RRRC) was established in 2001 to provide the biomedical community with the requisite infrastructure for archiving and distributing rat models. In the four years since the RRRC started, the RRRC has exceeded the 5-year goals by importing more strains (69) than we were funded to import (50) and by establishing not only a national repository and distribution center, but an international network of rat repositories that links biomedical researchers with rat models available in nearly every part of the world. The RRC has also accepted another 176 rat lines from the NIH rat repositories. Additionally, research performed at the RRRC significantly advanced cryobiology, infectious disease detection and assisted reproductive technologies (ART) for the rat. The RRRC has become an essential resource to in the worldwide community of animal-based research. The Specific Aims of this proposal build on the strengths of the established repository and distribution functions of the RRRC and focus research efforts on developing technologies to overcome current impediments to rat research. To accomplish these goals, the following Specific Aims are proposed: 1. A major goal of this proposal is to expand and improve the repository and distribution functions of the RRRC by (a) actively recruiting rat models into the Center, (b) increasing the efficiency for archiving and reanimating rat lines, (c) continuing to foster the international network of rat repositories, (d) continuing to distribute high quality rats, (e) making rat tissues and reagents available, and (f) aggressively disseminating information about the RRRC and the services it can provide to investigators. Together these efforts will result in a resource that meets the needs of the global biomedical research community. 2. To conduct research aimed at providing new services and technologies that will benefit researchers throughout the scientific community who use rats. Research projects will include developing : (a) purified recombinant rat luteinizing hormone (rl_H) and rat follicle stimulating hormone (rFSH) to develop improved protocols for superovulation of rats;and (b) innovative biosensor technologies to enhance detection of infectious agents in laboratory rats.